why do I feel this way

I feel so much Resentment towards him. I can't get over the fact that he almost kicked me out
Of the house when he accused me of deleting some video and some pictures of his kids in his computer. A couple of days before that happened, I came across some pictures of him and his ex on his computer which I let him know about. He went ahead and deleted them and the day he did he decided to pick me up from work later that night. As soon as I got in the car, he went off on me about some videos and pictures that were deleted. I told him I had not deleted anything when I came across all those pictures. We got home that night and he started throwing my clothes on the floor. I was upstairs with our roommate at the time told me my partner had mentioned a sex video of him and his ex being deleted which was the one I was being accused of. I decided to leave that night and the next morning he was apologizing so I came back. He gave me the sweet talk about how he didn't know why he reacted that way and whatsoever... we were good ever since and one time after an argument we had again over something stupid, I told him I was going to take off for the day so we could both have our space.. but it only went so far after he Came to me and started to cry talking about how much he loves me and how he knows
He hasn't been treating me good.... all this happened the first months we were living together.. 
Fast forward to a year now and we've been great. He shows me he loves me and cares a lot about me. He literally treats me like gold. And we're also expecting a baby! But the resentment I feel towards him doesn't go away. I've tried to let it go but I feel like I'm holding a grudge. I would never cheat on him or do anything behind his back, I love him too much. I also don't want to bring it up because we're so good I don't want to ruin... what can I do to make myself feel better? I feel heartbroken almost. I